Tank Level Sensors: Radar, Ultrasonic or Hydrostatic?

Use the working record

Download the editable worksheet. Record the actual evidence and responsible reviewer against each relevant row. The empty results are inputs for your project, not completed tests. Add the equipment identity, operating period and reference method before assigning an outcome. Retain unsuccessful checks and the evidence from any repeat after correction.

Write down the measurement problem

Identify the tank geometry, liquid, operating range, access and required output. The project may need a replenishment alarm, a level trend or a defensible volume estimate. Those uses can require different reference quality and installation effort. State the useful decision and expected operating conditions before selecting an instrument.

Record obstructions, agitation, filling arrangements, foam or vapour conditions where relevant. Obtain the actual device documentation for the proposed model. A general technology comparison can narrow the selection, but it cannot establish suitability for every combination of liquid, vessel and installation.

Understand the radar measurement path

Radar level instruments use electromagnetic signals and the returned response to determine distance under the selected device's method. Review the beam geometry, mounting requirements and usable measurement range in the supplier documentation. Internal structures, the filling path and the liquid surface can affect the installation assessment.

Confirm the reference point from which distance is measured and how the application converts it to level. Record the accepted empty and full references. A physically suitable radar instrument can still produce a misleading report if the configured reference or orientation does not match the actual tank.

Review the ultrasonic operating conditions

Ultrasonic instruments use an acoustic path to infer distance. Their suitability depends on the actual path and the selected instrument's compensation and operating limits. Review headspace conditions, obstructions, mounting and the specified near-field or unusable region. Keep the manufacturer's model-specific requirements with the proposal.

Plan how the installation will be checked under representative filling and operating conditions. An open, still-water demonstration may not represent the intended vessel. The acceptance record should identify the actual conditions observed and any condition still requiring verification.

Make hydrostatic assumptions explicit

A hydrostatic measurement relates pressure to liquid head under the applicable density and pressure-reference assumptions. Identify whether the selected instrument is vented, absolute or otherwise referenced, and how the system handles atmospheric or vessel pressure where relevant. The responsible specialist should confirm the method for the particular installation.

Document the liquid characteristics, mounting depth and fixed reference. A density change can affect the relationship between pressure and inferred level. Cable protection, vent management where applicable, fouling and retrieval access also influence the maintainability of a submerged arrangement.

Keep the vessel conversion separate

Level is a measurement; volume is a calculation using the vessel relationship. A vertical rectangular tank with a verified constant cross-section can use a simple geometry over the relevant range. A horizontal cylindrical tank or irregular reservoir needs the appropriate relationship. A percentage level should not automatically be labelled percentage volume.

Retain the curve or formula source, valid range and version. Where the tank has changed or its dimensions are uncertain, obtain the required survey or calibration evidence. The sensor supplier's accuracy specification does not validate the geometry used in the reporting software.

Plan an independent reference comparison

Agree a safe local reference and a practical set of operating points. The metering or water-system specialist determines the method and acceptable uncertainty. Record the instrument reading, reference observation, time and conditions together. A comparison taken while the level changes rapidly needs a method that accounts for timing.

Keep adjustment and verification separate in the record. If a zero or offset is changed, retain the original result, reason and subsequent check. The acceptance pack should show which configuration was finally accepted and how a later technician can repeat the comparison.

Compare total installed effort

Include access equipment, mounting, cable work, power, communication, configuration and local reference checks in the quotation. Different methods can shift cost between the instrument and the installation. A low device price may not represent the lower cost of obtaining a maintainable measurement at the actual vessel.

Add routine inspection, cleaning or retrieval requirements and the practical replacement method. Consider whether the site's staff can perform the agreed checks safely and whether a replacement needs a specialist visit. Use current supplier quotations rather than a generic price range detached from the installation.

Accept the reading through to the operating response

Verify the point identity, unit, range, acquisition time and quality state in the application. Test the agreed missing-data indication and any level-based notification using an authorised method. The responsible operator should understand the difference between a measured low level and an unavailable measurement.

At handover, provide the installed photograph, reference details, accepted conversion and maintenance instruction. A later sensor replacement should preserve the vessel identity while recording the changed instrument and configuration. The useful outcome is a reading the team can verify and interpret, with a known route for resolving discrepancies.

Connect the decision to the project

Use Water management, Remote water monitoring, Water utilities to place this task within the wider installation. Bring a recent operating record and identify the decision that the proposed measurement should support. A focused discussion should establish the first boundary, the responsible site participants and the evidence needed before expanding the scope.

Agree who maintains the point register and who can change interpretation rules. Preserve the previous version when a device, product, reporting period or responsibility changes. During handover, demonstrate an export that another authorised person can reconcile without relying on the dashboard operator to explain missing fields.

Discuss the scope with addanode using the actual site information, available interfaces and proposed acceptance record.

Sources and method

The VEGA radar instrument page and hydrostatic instrument page provide examples of documented measurement methods. They are method references, not a universal product recommendation or a claim about addanode supply specifications.

Frequently asked questions